Reserve refrigerant supply and apparatus



Sept. 29, 1936. A R ZW|CK| 2,055,780

RESERVE REFRIGERANT SUPPLY AND APPARATUS Filed July 17, 1954 `Patented Sept. 29, 19,36

PATENT OFFICE RESERVE RERIGERANT SUPPLY AND APPARATUS Joseph It. Zwckl, Philadelphia, Pa., assignor to Baldwin-Southwark Corporation, a corporation of Delaware Application July 17, 1934, SerialNo. 735.661

12 Claims.

'I'his invention relates generally vto a refrigerating system and more particularly to improved means for compensating for refrigerant leakage from the system.

A great deal of difiiculty has been experienced in refrigeration systems of moderate capacity due to leakage of the refrigerant, this being especially true with refrigerating systems used in air conditioning apparatus for railroad cars as in this case a train usually stops for only very short intervals of time before reaching its destination, and hence it is either impossible to recharge the system until the destination has been reached or any attempt to recharge the system while the trainmomentarily stops at intermediate stations will result in inconvenience or train delay together with an excessive maintenance cost caused by the fact that it would be impossible to predetermine the 'station at which the recharging might be necessary. Hence a large number of service stations should be maintained if full normal air conditioning is to be maintained throughout the trip. However, it is well-known to be impractical to provide such service facilities, and hence cars 2 5 often travel a considerable distance and length of time without thecomfort of air conditioning. It is one object of my invention to overcome these dimculties in a relatively simple and effective manner by providing a reserve supply of refrigerant carried by the train to supply' make-up refrigerant to the refrigerating system automati- 'cally when needed. While my invention is particularly adapted for railroad cars, yet it is equally adapted to other refrigerating apparatus whether 35 for general air conditioning purposes or otherwise.

A further object is to provide improved control means that is operative to maintain a substantially constant amount of refrigerant in the system irrespective of normal pressure fluctuations there- 40 in. Another object of my invention is to provide an improved apparatus and system whereby a reserve supply of refrigerant may be supplied to a refrigerating system automatically in accordance with variations from normal pressure conditions in the refrigerating system.

'A still further object is to provide improved means for maintaining a substantially constant amount of refrigerant in the system irrespective oi' pressure variations created therein by changes in the temperature of a medium to be cooled by the evaporator. In air conditioning apparatus, either air or water -is circulated over the evapo- ,rator to cool the car, rooms or other enclosures,

and the temperature of such medium will vary during the course of the day and night and particularly when it is being initially cooled. It is during such periods that pressure conditions in the refrigerating system may vary from a maximum to a minimum even with a normal amount of refrigerant in the system. Hence in control- 5 ling the addition of reserve refrigerant to the system in accordance with the pressure thereof, it is necessary to take into consideration the foregoing' conditions and in this respect it is a more specic object of my invention to provide iml0 proved means for imposing a compensating action on the reserve supply control mechanism automatically in accordance with variations in the temperature of the medium to be cooled by the evaporator, this being equivalent-to the rate of 15 evaporation or evaporator temperature.

Otherobjects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawing in which: 20

Fig: 1 is a diagrammatic view of a compressor-- condenser-evaporator refrigerating system with my improved reserve supply means associated therewith;

Fig. 2'is an enlarged sectional view of the re- 25 serve supply control valve. v

In the illustrated embodiment of the invention which is shown herein merely for the purpose of disclosing one specific form among possible others that the invention might take, I have provided a. 30 refrigerating system including usual elements such as a compressor I, high pressure discharge line 2, condenser 3, expansion valve mechanism 4 of any suitable type, evaporator 5 and suction line 6 which maylead either directly to the suction 35 ports of the compressor or to the crankcase 'I in case the compressor is of the type which employs the crankcase as a suction chamber. Connected to the low side of the refrigerating system, specifically to the crankcase 1, is a reserve supply of 40 refrigerant 8 adapted to have any usual form of removable connection, diagrammatically indicated at 9, to a pipe I0 leading to a control means v generally indicated at I I.

As shown in Fig. 2, the control means prefer- 45 ably comprises a two part casing I2 and I3 with.

by a fluted guiding member 2I while a spring 22 is interposed between member 2I and an adjustable plug 23. Plug 23 may be soldered or otherwise hermetically sealed in any adjusted position'. Leading from chamber I5 is a pipe 24 connected either to the suction chamber in crankcase 1 or to the suction line 6. In the event 4of said connection being secured to the suction line 6, it is preferable that a relatively small orifice should be inserted in line 24 to minimize pressure variations in the system reacting back on the diaphragm I4. These pressure fluctuations are usually at a minimum in the crankcase, and hence pipe 24 can be connected directly thereto without interposing the restricted orice in line 24.

The temperature compensating mechanism comprises an outer bellows 26 whose ends are hermetically sealed to diaphragm I4 and to the outer end of an inner bellows 2'I. The free end of bellows 21 is hermetically secured to a flange of a spring casing 28, thereby providing a thermostatic pressure chamber 29. This chamber is connected by a small pipe 30 to a thermostatic bulb 3| placed in the path of inlet air or other medium flowing over the evaporator 5. A spring 32 is interposed between diaphragm I4 and the closed end of casing 28 while an adjustable screw 33 is adapted to vary the tension of spring 32.

Operation-When the refrigerating system contains its normal charge so as to not require the supply of any make-up refrigerant, the suction pressure is then of a predetermined value,

thereby causing the pressure within chamber I5 to act on diaphragm I4 to move the same against the force of spn'ng 32 to move valve I8 to close port I8. If the temperature of the air or other medium flowing over evaporator 5 should decrease to such a point that very little evaporation takes place, thereby causing the suction pressure to drop, this decreased temperature of the medium is transmitted from thermostatic bulb 3| through pipe 30 to the thermostatic chamber 29,

thereby reducing the pressure of the thermostatic liquid therein and thus compensate for the reduced pressure on the other side of the diaphragm in chamber I5. Conversely if the temperature of the medium owing over evaporator 5 should increase above some predetermined value, then a greater rate of evaporation will take place with a consequent increase in suction pressure. Said increased temperature of the medium will be transmitted from thermostatic bulb 3| to the chamber 29, thereby increasing the pressure on the left side of diaphragm I4 to maintain a predetermined diiferentialewithhe increased pressure in chamber I5. If refrigerant should leak from the system with consequent reduction in suction pressure, then this reduced pressure is transmitted to chamber I5 thereby permitting spring 32 to move valve I8 to open port I6 whereupon reserve refrigerant is supplied from tank 8 through pipe I0 past fiuted guide member 2l and through port I6 to chamber I5 and pipe 24 to the suction side of. the refrigerating system. As the suction pressure increases to normal, the pressure in chamber I5 will correspondingly increase until valve I8 closes its port I6. It will of course be understood that the pressure of the reserve supply of refrigerant is always greater than the suction pressure during normal operation of the reserve supply.

As a result of the foregoing construction and mode of operation, it is seen that a reserve supply tank may be connected to the refrigerating system of any air conditioning apparatus thereby insuring uniform comfort and operating conditions irrespective of any refrigerant leakage, while at the same time insuring automatic operation of the reserve system irrespective of normal variations in suction pressure or variations due to changes in the temperature of the medium to be cooled by the evaporator. If desired, this reserve system may be applied to a reverse cycle refrigerating system used for heating or cooling merely 4by placing a second thermostatic bulb 3|' in the path of medium flowing over condenser 3. This bulb 3I may be connected tothermostatic pipe 30 by a three-way valve or other suitable control 33, thus permitting only the bulb to be operative which is associated with the heat exchange element functioning as an evaporator. While a compressor-condenser-evaporator circuit has been shown, it will of course be understood that my reserve supply system may be applied to any refrigerating system employing high and low sides as the broad principle involved herein is to maintain a constant amount of working refrigerant, that is, refrigerant in the refrigerating system, in accordance with variations from normal.

It will of course be lunderstood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim: j

l. In combination, a closed refrigerating system, a reserve supply of refrigerant normally vmaintained separate from said system, and

system.

3. In combination, a refrigerating system, a reserve supply of refrigerant, a valve controlled passage through which refrigerant is admitted from saidgreserve supply to said system, and means responsive to variations from a predetermined pressure diiferential for opening said valve to permit said addition of refrigerant to the system.

4. In combination, a refrigerating system, a reserve supply of refrigerant, means for adding refrigerant to said system from said reserve supply automatically in accordance with a diminution of refrigerant in the system, and thermostatic compensating means for controlling said latter means.

5. In combination, a refrigerating system, a reserve supply of refrigerant, a valve mechanism for controlling the addition of refrigerant from said supply to said refrigerating system automatically in accordance with a diminution of refrigerant therein, and adjustable means for varying said admission of reserve refrigerant.

6. In combination, a refrigerating system, a reserve supply of refrigerant, a valve mechanism for controlling the addition of refrigerant from said reserve supply to said system, a movable member controlling said valve mechanism and subjected on one side to refrigerant pressure in said system and on the other side to a predetermined force.

,7. The combination set forth in claim 6 further characterized by the provision of means for adjusting the value of said force.

8. In combination, a refrigerating system, a reserve supply of refrigerant, a valve mechanism for controlling the addition of reserve refrigerant to said system, a movable member connected toV said valve, means for subjecting one side of said movable member to fluid pressure in said system, and therm'ostatic control means -for subjecting the other side of said movable member to a predetermined force.

9. In combination, a refrigerating system including an evaporator, a reserve supply of refrigerant, means for adding refrigerantto said system for said reserve supply automatically in accordance with a diminution of refrigerant in the system, means for also controlling said addition of refrigerant to said system automatically in accorda-nce with the temperature of a medium flowing over said evaporator.

10. In combination, a refrigeratingV system having a compressor-condenser-evaporator circuit, a reserve supply of refrigerant, and means responsive to the suction pressure of said circuit and to the temperature of the medium flowing over said evaporator for controlling the addition of refrigerant from said reserve supply to said system.

11. In combination, a refrigerating system having a compressor with a suction chamber, a condenser, an evaporator, a reserve supply of refrigerant, a valve mechanism for. controlling the addition of refrigerant from said reserve supply to said suction chamber automatically in accordance with diminution of refrigerant in the system, and means for also controlling said addition automatically in accordance with temperature changes in a medium flowing over said evaporator.

12. In combination, a refrigerating system having a pair of complementary high and low pressure heat exchange elements, a reserve supply of refrigerant, valve mechanism for controlling the addition of refrigerant to said system from said reserve supply, and means for also controlling said addition automatically in accord-A ance with the temperature of a medium owing over whichever one of said heat exchange elements may be functioning as an evaporator.

JOSEPH R. ZWICKL. 

